Sound pick-up unit



Aug 29, 1939 F. J. coYER 2,171,173

SOUND PICK-UP UNIT Filed Deo. ll, 1936 2 Sheets-Sheet 2 In ven forFrmzfz' Jaye 7,"

Patented Aug. 29, 1939 SOUND PICK-UP UNIT Application December 11,1936', Serial No. 115,399

2- Claims.

The present invention appertains to new and useful improvements in soundpick-up units, which are mainly designed forlocating leaks in watermains.

The principal object of the present invention is to provide a device ofthe character stated whereby leaks can be detected by simply amplifyingthe sound vibration emanating from the leaky portion of the main, andtraveling through the ground.

Another important object of the invention is to provide a device whichis substantially foolproof and positive acting in operation.

In the drawings:

Figure l is a fragmentary vertical sectional view through the soundlocating unit.

Figure 2 represents a horizontal sectional view taken substantially onthe line 3-3 of Figure 1.

Figure 3 is a plan View of the lead block.

Figure 4 is a View looking into one of the cupshaped members.

Figure 5 is a top plan View of the lead block housing.

Figure 6 represents a fragmentary side elevational view partly insection of the sound locating unit grounding engaging tip.

As shown in these drawings, the sound locating unit consists of acylindrical shell I1 within the lower portion of which is secured thecircular housing I8 of steel which has a squareshaped opening I9 at itscentral portion, receiving the block 20 of lead.

The top and bottom sides of the assembly consisting of the housing I8and block 20 are concave and over these concaved sides are disposed thediaphragms 2l-22. The block of lead 25J is provided with an opening 23therethrough and through this is disposed the bolt 24, the head at oneend of the bolt engaging the diaphragm 22 while the nut at the oppositeend of the bolt engages the diaphragm 2|. The bolt is in rigidengagement with the lead block.

A cup-like structure 25 is disposed into the lower portion of the shelll1 so as to define a sound chamber for the lower diaphragm 22. This cup25 has a central opening 26 therein and is covered by a thin plate 2l.

'I'he disk 2l has a cup-like structure 28 disposed thereover to dene asound chamber 29 for the diaphragm 2l and over this is disposed the thinplate 30 upwardly from the central portion of which extends the smalltube 36 which extends through the sponge rubber disk 3l.

A pair of bracket members 32 extend upwardly from the plate 30 andsupport the microphone (Cl. ITL-352.7)

33 from which the conductor l extends. A sound funnel 34 extends to themicrophone 33 and has its lower edge bearing against the disk 3l.

Tie bolts 35 extend through the sound boxes below and above thediaphragms 2l-22 as well as through the plates 21-39 and the brackets 32for holding these units together in rigid assembly.

When the device is placed on the ground and there is any noise in thevicinity, such as the sound of water escaping from pipes, energy istransmitted as wave motion to the earth and the earth waves shake thedevice. The lead block remains comparatively motionless, and thusrelative motion occurs between the case and the weight, causing the airin the cup-shaped members 25 and 28 to be compressed and ratified. Theair pulsations are transmitted through the tube 30 and funnel 34 to themicrophone. The conductor 6 leads to an amplier to which may beconnected a loud speaker.

As is shown in Figures 1 and 6, the unit 5 has an elongated tube 36extending from the top of its shell terminating in a solid head portion3l to which a driving point 38 is secured by the threaded shank 39, sothat when desired as when soft ground is available, the pointed end ofthe sound locator can be driven into the ground to catch the vibration.

While the foregoing specification sets forth the invention in specificterms, it is to be understood that numerous changes in the shape, sizeand materials may be resorted to without departing from the spirit andscope of the invention as claimed hereinafter.

What is claimed as new is:

l. In a device of the class described, a shell having its bottom open, aplate extending across the bottom, a vibratory block located in theshell above the plate, diaphragms extending across the upper and lowerfaces of the block and having their major portions spaced therefrom, abolt connecting the block with the diaphragm, upper and lower cup-shapedmembers forming air chambers above and below the diaphragms, eachcup-shaped member having a centrally arranged opening therein, a thinplate resting on the upper cup-shaped member and having a tubular partin communication with the upper cup-shaped member through the openingtherein, a resilient member seated on the plate and surrounding thetubular part, brackets resting on the upper plate, screws connecting thebrackets, the plates, the cup-shaped members, the diaphragms and theblock together, a microphone supported by the brackets and a funnelhaving its large lower end resting on the resilient member and its smallend engaging the microphone.

2. In a device of the class described, a shell having its bottom open, athin plate extending across the opening, a steel block supported in theshell `above the plate and having a centrally arranged opening therein,a lead member fitting in the opening of the steel member, said steelmember and the lead member forming a Vibratory block the upper and lowerfaces of which are substantially concave, upper and lower diaphragmplates extending across said faces, a central member rigidly connectedwith and passing through the lead member and having its ends connectedwith the diaphragm plates, a cupshaped member having its flangesengaging the lower diaphragm plate and resting on the firstmentionedplate and having a centrally arranged opening therein, an uppercup-shaped member having its flanges resting on the upper diaphragmplate and having a centrally arranged opening therein, a thin plateresting on the upper cupshaped member and having a centrally arrangedtubular part, brackets resting on the upper thin plate, screws passingthrough portions of the brackets, the upper thin plate, the cupi-shapedmembers, the diaphragm plates, and the vibratory plate and having theirlower ends connected with the first mentioned plate, a microphonesupported by the brackets, a resilient member resting on the centralportion of the upper thin plate and surrounding the tubular part thereofand a funnel having its largeV lower end resting on the resilient memberand its upper end engaging the microphone.

FRANCIS J. COYER.

